Thicknessing gauge



FIG. 1 is a perspective view of the thicknessing gauge;

FIG. 2 is a top side view thereof;

FIG. 3 is a left view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a back view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in FIGS. 1–7 show environmental structure and form no part of the claimed design. 

The ornamental design for a thicknessing gauge, as shown and described. 